Equilibrium and kinetic study of sodium-and potassium-induced conformational changes of apo-α-lactalbumin

Equilibrium and kinetics of Na+-and K+-induced conformational changes of apo-α-lactalbumin were studied by means of circular dichroism. While apo-α-lactalbumin was considerably unfolded in the absence of Na+ or K+ in 20 mM Tris at pH 8.0 and 25°, both the monovalent cations restored the tertiary structure of the protein. Apparent binding constants of Na+ and K+ to the apoprotein were estimated from the equilibria of the Na+- and K+-induced conformational changes. Based on kinetic data of the conformational changes induced by the monovalent cations, binding mechanism of the ions to the apo-protein was examined. Bound alkali-metal ions stabilize the native-like state and an activated state in the unfolding-refolding reaction of the apoprotein.     

Small mass lesions in cirrhosis: Transition from benign adenomatous hyperplasia to hepatocellular carcinoma?

Abstract Ten patients with cirrhosis, in whom small mass lesions were detected by imaging techniques and histological diagnosis of the resected specimens was difficult, are described. There were 17 grossly discrete lesions measuring 10 × 8 mm to 27 × 22 mm. Four were compatible with so-called adenomatous hyperplasia showing no histological features of malignancy, and eight were equivocal as to whether they were benign or malignant. The other five lesions (in four patients) were hepatocellular carcinoma, co-existing with apparently benign lesions. The eight equivocal lesions were eventually judged to be highly differentiated hepatocellular carcinomas. These benign-appearing lesions, found by advanced imaging in patients with cirrhosis, create a serious problem in regions where primary liver cancer is endemic among cirrhotics, and hepatic resection is the preferred treatment.
It is possible that these lesions represent a transition from adenomatous hyperplasia occurring in cirrhotic livers to hepatocellular carcinoma through a histologically equivocal state and that the current morphological methods are inadequate for differentiating malignant from benign lesions.     

Primary adenocarcinoma of the rete testis with preceding diagnosis of pulmonary metastases

We report a case of primary adenocarcinoma of the rete testis in a 55-year-old man with pulmonary metastases that were detected 11 months prior to the diagnosis of the primary lesion. Primary adenocarcinoma of the rete testis is an extremely rare malignant tumor with a poor outcome. The most common primary symptom is a scrotal mass, often accompanied by hydrocele and chronic epididymitis. The diagnosis is often delayed because of non-specific clinical presentation and symptoms. We cannot forget that rete testis is a possible primary site for a primary, unknown metastatic adenocarcinoma.     

Adenosine-Sensitive Atrial Reentrant Tachycardia Originating from the Atrioventricular Nodal Transitional Area

Adenosine-Sensitive AT from AVN Area. Introduction : Atrial tachycardia shows wide variations in its electrophysiologic properties and sites of origin. We report an atrial tachycardia with ECG manifestations and electrophysiologic characteristics similar to an atypical form of AV nodal reentrant tachycardia (AVNRT).
Methods and Results : This supraventricular tachycardia was observed in 11 patients. It was initiated by atrial extrastimulation with an inverse relationship between the coupling interval of an extrastimulus and the postextrastimulus interval. Its induction was not related to a jump in the AH interval, and its perpetuation was independent of conduction block in the AV node. Ventricular pacing during tachycardia demonstrated AV dissociation without affecting the atrial cycle length. A very small dose of adenosine triphosphate (mean 3.9 ± 1.2 mg) could terminate the tachycardia. The earliest atrial activation during tachycardia was recorded at the low anteroseptal right atrium with a different intra-atrial activation sequence from that recorded during ventricular pacing, where the tachycardia was successfully ablated in 9 of 10 attempted patients. Bidirectional AV nodal conduction remained unatttched after successful ablation.
Conclusion : There may he an entity of adenosine-sensitive atrial tachycardia probably due to focal reentry within the AV node or its transitional tissues without involvement of the AV nodal pathways. This tachycardia can he ablated without disturbing AV nodal conduction from the right atrial septum.     

Intrahepatic expression of HBsAg and HBcAg in asymptomatic HBsAg carriers and its follow-up

Intrahepatic expression of hepatitis B surface antigen (HBsAg) and hepatitis B core antigen (HBcAg) was investigated in 46 asymptomatic HBsAg carriers by a direct immuno-fluorescent method. In 21 HBeAg positive carriers, HBsAg was expressed diffusely on the membrane of hepatocytes, with associated cytoplasmic localization in a few scattered hepato-cytes. HBcAg was expressed in the nucleus of many hepatocytes and in the cytoplasm of a few scattered hepatocytes, but not on the cell membrane. In 25 anti-HBe positive carriers, HBsAg was expressed on the surface and in the cytoplasm of hepatocytes diffusely and/or focally, but neither intrahepatic HBcAg nor serum HBV-DNA was detected. Repeat liver biopsies were performed in 17 patients. In eight of 13 HBeAg-positive HBsAg carriers, who developed histologically proven chronic hepatitis and liver cirrhosis, the localization of HBsAg in liver had changed from a membranous to a mixed (membrane and cytoplasm) pattern, and localization of HBcAg in liver had changed from a predominantly nuclear to a predominantly membranous and cytoplasmic pattern. However, in two HBeAg and two anti-HBe positive cases who showed no biochemical and histologic change at follow-up, the intrahepatic expressions of HBsAg and HBcAg in the second biopsies remained unchanged. Thus, decrease in membranous expression of HBsAg and increase in membranous and cytoplasmic expression of HBcAg were associated with progression to chronic liver disease. This suggests that membranous HBcAg may represent the major target in the process of injury to hepatocytes.     

Marked atrophy of the right lobe seen in idiopathic portal hypertension confirmed by laparoscopy

A 70‐year‐old‐male was hospitalized for the treatment of esophageal varices and close examination of the liver. Blood chemistry tests revealed mild liver dysfunction. Abdominal ultrasound and computed tomography scan revealed marked atrophy of the right and quadrate lobes of the liver without abnormalities of the biliary system. Abdominal angiography revealed marked atrophy of the right lobe of the liver, without obliteration in the portal venous system, but it could not be determined whether the atrophy was congenital or secondary. Subsequently performed laparoscopy revealed marked atrophy of the anterior segment of the right lobe and quadrate lobe with the whitish scarred edge demarcating the border between the edge and neighboring liver parenchyma. The liver surface appeared to be undulant, but non‐cirrhotic. These findings suggest secondary lobar atrophy of the liver, without cirrhosis. Liver biopsy of the left lobe showed the findings to be compatible with idiopathic portal hypertension (IPH), and we diagnosed IPH based on these findings and hepatic lobar atrophy was attributable to IPH. There have been few reports of cases with hepatic lobar atrophy associated with IPH, and the mechanism of atrophy is unclear. We report a case of IPH with marked liver atrophy in which laparoscopy is a decisive means whether liver atrophy is congenital or secondary.     

Update on Percutaneous Management of Chronic Total Occlusion

Management of chronic total occlusions (CTOs) remains a challenge for interventional cardiologists. Despite advances in the design of angioplasty hardware and increased operator experience, percutaneous angioplasty of CTO still is associated with a relatively low primary success rate compared with non-CTO. Although the stent has dramatically improved initial and long-term outcome, the incidence of restenosis and reocclusion continues to be high in patients with excessive lesion length and/or small vessel size. Adjunctive pharmacotherapy, such as platelet glycoprotein IIb/IIIa receptor antagonist, may play an important role in the prevention of early reocclusion as well as late restenosis. Similarly, radiation therapy may be useful in the prevention/treatment of in-stent restenosis. Although observational data have shown a poor long-term survival in patients with CTO, convincing prospective or randomized data are lacking. Future investigations will need to focus on the long-term outcome of patients with CTO referred for angioplasty compared with CABG or medical therapy.     

High Energy Radiofrequency Catheter Ablation for Common Atrial Flutter Targeting the Isthmus between the Inferior Vena Cava and Tricuspid Valve Annulus Using a Super Long Tip Electrode

There have been controversies concerning the optimal target sites and approaches in radiofre-quency catheter ablation of common atrial flutter. We attempted high energy radiofrequencv catheter ab-lation targeting the isthmus between the inferior vena cava and tricuspid valve annulus (IVC-TV isthmus) with a super long (8 mm) tip electrode, and compared the efficacy of this anatomical approach with the electrophysiological approach targeting the posteroseptal right atrium posterior to the coronary sinus us-ing a standard 4-mm tip electrode. Atrial flutter was successfully ablated in 12 of 12 patients (100%) with-out recurrence with the anatomical approach, while, in 7 of 9 patients (64%) with 2 recurrences with the electrophysiological approach. In comparison of ablation data between the anatomical and electrophysi-ological approaches, there were significant differences in the mean number of application pulses (anatomical vs electrophysiological: 2.3 ± 0.8 vs 9.9 ± 6.4, P < 0.01), applied wattage (39 ± 12Wvs24 ± 6W.P < 0.01), applied energy per application (1.986 ± 426 / vs 659 ± 323 J. P < O.O1), fluoroscopic time (26 ± 11 min vs 74 ± 30 minutes, P < 0.01), and procedure time (59 ± 8 min vs 181 ± 53 min. P < 0.01). In conclusion, the anatomical approach is superior to the electrophysiological one with respect to proce-dure and radiation time, and linear ablation at the IVC-TV isthmus with an 8-wm tip electrode and high energy application is highly effective and safe.     

Macroreentrant Atrial Tachycardia in Patients without Previous Atrial Surgery or Catheter Ablation: Clinical and Electrophysiological Characteristics of Scar‐Related Left Atrial Anterior Wall Reentry

Scar‐Related Left Atrial Anterior Wall Reentry. Introduction: Macroreentrant atrial tachycardia (MRAT) has been described most frequently in patients with prior cardiac surgery. Left atrial tachycardia and flutter are common in patients who undergo atrial fibrillation ablation; however, few reports describe left atrial MRAT involving the regions of spontaneous scarring. Here, we describe left atrial MRAT in patients without prior cardiac surgery or catheter ablation (CA) and discuss the clinical and electrophysiological characteristics of tachycardia and outcome of CA. Methods and Results: An electrophysiological study and CA were performed in 6 patients (3 men; age 76 ± 6 years) with MRAT originating from the left atrial anterior wall (LAAW). No patient had a history of cardiac surgery or CA in the left atrium. Spontaneous scars (areas with bipolar voltage ≤ 0.05 mV) were observed in all patients. The activation map showed a figure‐eight circuit with loops around the mitral annulus (4 counterclockwise and 2 clockwise) and a low‐voltage area with LAAW scarring. The mean tachycardia cycle length was 303 ± 49 milliseconds. The conduction velocity was significantly slower in the isthmus between the scar in the LAAW and the mitral annulus than in the lateral mitral annulus (0.17 ± 0.05 m/s vs 0.94 ± 0.35 m/s; P = 0.003). Successful ablation of the isthmus caused interruption of the tachycardia and rendered it noninducible in all patients. Conclusion: Spontaneous LAAW scarring is an unusual cause of MRAT, showing activation patterns with a figure‐eight configuration. Radiofrequency CA is a feasible and effective treatment in such cases. (J Cardiovasc Electrophysiol, Vol. 24, pp. 404‐412, April 2013)